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authorJan Kara <jack@suse.cz>2016-09-20 00:44:27 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-09-20 01:36:17 +0300
commit12703dbfeb15402260e7554d32a34ac40c233990 (patch)
treedaff806026a436ba9a359606c8eb580a9d9a7632 /fs/notify/group.c
parentd5bf141893880f7283fe97e1812c58ff22c8f9a5 (diff)
downloadlinux-12703dbfeb15402260e7554d32a34ac40c233990.tar.xz
fsnotify: add a way to stop queueing events on group shutdown
Implement a function that can be called when a group is being shutdown to stop queueing new events to the group. Fanotify will use this. Fixes: 5838d4442bd5 ("fanotify: fix double free of pending permission events") Link: http://lkml.kernel.org/r/1473797711-14111-2-git-send-email-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/notify/group.c')
-rw-r--r--fs/notify/group.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/fs/notify/group.c b/fs/notify/group.c
index 3e2dd85be5dd..b47f7cfdcaa4 100644
--- a/fs/notify/group.c
+++ b/fs/notify/group.c
@@ -40,6 +40,17 @@ static void fsnotify_final_destroy_group(struct fsnotify_group *group)
}
/*
+ * Stop queueing new events for this group. Once this function returns
+ * fsnotify_add_event() will not add any new events to the group's queue.
+ */
+void fsnotify_group_stop_queueing(struct fsnotify_group *group)
+{
+ mutex_lock(&group->notification_mutex);
+ group->shutdown = true;
+ mutex_unlock(&group->notification_mutex);
+}
+
+/*
* Trying to get rid of a group. Remove all marks, flush all events and release
* the group reference.
* Note that another thread calling fsnotify_clear_marks_by_group() may still
@@ -47,6 +58,14 @@ static void fsnotify_final_destroy_group(struct fsnotify_group *group)
*/
void fsnotify_destroy_group(struct fsnotify_group *group)
{
+ /*
+ * Stop queueing new events. The code below is careful enough to not
+ * require this but fanotify needs to stop queuing events even before
+ * fsnotify_destroy_group() is called and this makes the other callers
+ * of fsnotify_destroy_group() to see the same behavior.
+ */
+ fsnotify_group_stop_queueing(group);
+
/* clear all inode marks for this group, attach them to destroy_list */
fsnotify_detach_group_marks(group);